Index: clang/lib/Driver/ToolChains/CommonArgs.cpp
===================================================================
--- clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -1234,7 +1234,14 @@
   case ToolChain::UNW_CompilerRT:
     if (LGT == LibGccType::StaticLibGcc)
       CmdArgs.push_back("-l:libunwind.a");
-    else
+    else if (TC.getTriple().isOSCygMing()) {
+      if (LGT == LibGccType::SharedLibGcc)
+        CmdArgs.push_back("-l:libunwind.dll.a");
+      else
+        // Let the linker choose between libunwind.dll.a and libunwind.a
+        // depending on what's available, and depending on the -static flag
+        CmdArgs.push_back("-lunwind");
+    } else
       CmdArgs.push_back("-l:libunwind.so");
     break;
   }
Index: clang/test/Driver/compiler-rt-unwind.c
===================================================================
--- clang/test/Driver/compiler-rt-unwind.c
+++ clang/test/Driver/compiler-rt-unwind.c
@@ -48,3 +48,26 @@
 // RUN:     --gcc-toolchain="" \
 // RUN: FileCheck --input-file=%t.err --check-prefix=RTLIB-GCC-UNWINDLIB-COMPILER_RT %s
 // RTLIB-GCC-UNWINDLIB-COMPILER_RT: "{{[.|\\\n]*}}--rtlib=libgcc requires --unwindlib=libgcc"
+//
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     --target=x86_64-w64-mingw32 -rtlib=compiler-rt --unwindlib=libunwind \
+// RUN:     -shared-libgcc \
+// RUN:     --gcc-toolchain="" \
+// RUN:   | FileCheck --check-prefix=MINGW-RTLIB-COMPILER-RT-SHARED-UNWINDLIB-COMPILER-RT %s
+// MINGW-RTLIB-COMPILER-RT-SHARED-UNWINDLIB-COMPILER-RT: "{{.*}}libclang_rt.builtins-x86_64.a"
+// MINGW-RTLIB-COMPILER-RT-SHARED-UNWINDLIB-COMPILER-RT: "{{.*}}l:libunwind.dll.a"
+//
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     --target=x86_64-w64-mingw32 -rtlib=compiler-rt --unwindlib=libunwind \
+// RUN:     -static-libgcc \
+// RUN:     --gcc-toolchain="" \
+// RUN:   | FileCheck --check-prefix=MINGW-RTLIB-COMPILER-RT-STATIC-UNWINDLIB-COMPILER-RT %s
+// MINGW-RTLIB-COMPILER-RT-STATIC-UNWINDLIB-COMPILER-RT: "{{.*}}libclang_rt.builtins-x86_64.a"
+// MINGW-RTLIB-COMPILER-RT-STATIC-UNWINDLIB-COMPILER-RT: "{{.*}}l:libunwind.a"
+//
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     --target=x86_64-w64-mingw32 -rtlib=compiler-rt --unwindlib=libunwind \
+// RUN:     --gcc-toolchain="" \
+// RUN:   | FileCheck --check-prefix=MINGW-RTLIB-COMPILER-RT-UNWINDLIB-COMPILER-RT %s
+// MINGW-RTLIB-COMPILER-RT-UNWINDLIB-COMPILER-RT: "{{.*}}libclang_rt.builtins-x86_64.a"
+// MINGW-RTLIB-COMPILER-RT-UNWINDLIB-COMPILER-RT: "{{.*}}lunwind"